Techniques such as those of Patent Documents 1 and 2 have been proposed as techniques for charging a power storage unit using power from a power source unit. Patent Document 1 discloses a configuration in which a battery and an electric double layer capacitor are connected by a path-interrupting switching element and a current limiting resistor, with the electric double layer capacitor being charged while current is limited by the current limiting resistor. Patent Document 2 discloses a configuration in which a battery and an electric double layer capacitor are connected by a step-down DC-DC converter, and this technique provides a configuration in which the electric double layer capacitor is charged while controlling current using switching operations of a switching element.